WLAN Access Point Synchronization via PoE Piggybacked DS-SS Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless local area networks (WLANs) with multiple access points experience interference due to overlapping cell coverage, and current synchronization methods require additional overhead and components, which is inefficient and unreliable.
Innovation Solution
The use of Power over Ethernet (PoE) technology to 'piggyback' direct-sequence spread spectrum (DS-SS) synchronization signals onto power signals within Ethernet cables, allowing for efficient distribution to access points without additional overhead, enabling greater frequency reuse and minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If master beacon synchronization method is used, then access points can be synchronized, but additional receiving and synchronization components are required at each access point
Solution Approach 1:
The patent combines the synchronization signal transmission with the existing Power over Ethernet infrastructure. The PoE cables that already carry power to access points are used to carry both power and synchronization signals, merging two functions into a single existing infrastructure channel, thereby avoiding additional dedicated synchronization hardware
Solution Approach 2:
The PoE cable system is made multi-functional by enabling it to carry both power delivery and synchronization signaling functions simultaneously. This universal utilization of existing infrastructure eliminates the need for separate synchronization componentry at each access point
2Object-affected harmful factors
If frequency reuse pattern is implemented to minimize interference, then available frequencies must be carefully managed, but frequency resources are limited
Solution Approach 1:
The patent implements time-division multiplexing where access points transmit on the same frequency channel at different time intervals based on synchronization signals. This periodic action allows multiple access points to reuse the same frequency resource efficiently by transmitting in designated time slots, thereby increasing frequency resource utilization while maintaining low interference through temporal separation
3Reliability
If additional synchronization components are added to each access point, then synchronization can be achieved, but overhead and system complexity increase
Solution Approach 1:
The patent uses the existing PoE power delivery infrastructure as an intermediary carrier for synchronization signals. Rather than adding dedicated synchronization hardware to each access point, the system uses the already-deployed power cables as a mediator to deliver both power and synchronization information, thereby achieving accurate synchronization without increasing access point complexity
Data Source
AI summary
An arrangement for providing synchronization between a number of overlapping area access points within a wireless LAN utilizes an Ethernet cable connection to transmit synchronization signals from a centralized hub/switch to each of the access points connected to the cable. The synchronization signal takes the form of a direct sequence spread spectrum (DS-SS) signal. At each access point, a filter is used to recover the synchronization signal, allowing for the group of access points to share a common beacon signal and allowing frequency re-use among the access points.